Bootloader_K05 - A fork of Erik Olieman's bootloader for the KL05Z…

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A fork of Erik Olieman's bootloader for the KL05Z32. The bootloader is placed in the 29th sector allowing for 28kB of program memory. The 32nd sector is left empty after the bootloader to allow for use of the non volatile storage without the risk of overwriting it during serial firmware update.

Dependencies: mbed-dev

Fork of Bootloader_K64F by Erik -

This is a simple boot loader which resides at the end of the flash banks of your uController. It has be ported to work with the KL05Z. Porting the code to another Free scale uController requires the following changes:

Step 1 Change the address of the following function address

If your uController of choice has a flash size other than 32kB then you will likely want to change the addresses of following functions (current addresses displayed).

bootloader.cpp
0x7000 bootloader
0x7080 setupserial
0x70A0 write

FreescaleIAP.cpp
0x7268 erase_sector
0x7300 program_flash
0x7500 flash_size
0x7600 program_word
0x7700 run_command
0x7800 check_boundary
0x7900 check_align
0x7A00 verify_erased
0x7B00 check_error

Step 2 Follow the serial_api HAL file of your target

You will be unable to access anything that you don't define yourself in the bootloader. For this reason you need to create a function for serial. Look up and follow your target's serial_api.c file.

__attribute__((section(".ARM.__at_0x7080"))) static void setupserial(void) {
        //Setup USBRX/USBTX pins (PTB1/PTB2)
        //Enable Port B Clock
        SIM->SCGC5 |= 1 <<SIM_SCGC5_PORTB_SHIFT;                   
        //Select MCGFLLCLK clock
        SIM->SOPT2 |= 1 <<SIM_SOPT2_UART0SRC_SHIFT;
        //Select Pins PB1 & PB2 to their ALT3 function (RX & TX respectively)
        PORTB->PCR[1] = (PORTB->PCR[1] & ~0x700) | (3 << 8);
        PORTB->PCR[2] = (PORTB->PCR[2] & ~0x700) | (3 << 8);
        //Set UART0 Clock to be enabled
        SIM->SCGC4 |= SIM_SCGC4_UART0_MASK;
        //Set UART Baud Rate Register
        //Value's gathered expirimentally   
        UART0->BDH = 1;
        UART0->BDL = 56;   
        //Enable UART0
        UART0->C2 |= (UARTLP_C2_RE_MASK | UARTLP_C2_TE_MASK);
}

To set the correct baudrate you need to determine the right values for BDH & BDL registers for your clock speed. An easy way to do that is by simply printing them with the clock speed that you want like so:

#include "mbed.h"

Serial pc(USBTX, USBrX);

int main()
{
    while (1) {
        pc.printf("BDH: %d \n", UART0->BDH); // print the value of BDH Register
        pc.printf("BDL: %d \n", UART0->BDL); // print the value of BDL Register
        pc.printf("SOPT2: %d \n", SIM->SOPT2); // print the value of SOPT2 Register
        pc.printf("SCGC5: %d \n", SIM->SCGC5); // print the value of SCGC5 Register
        pc.printf("SCGC4: %d \n", SIM->SCGC4); // print the value of SCGC4 Register
        pc.printf("C2: %d \n", UART0->C2); // print the value of C2 Register
        pc.printf("C4: %d \n", UART0->C4); // print the value of C4 Register
        wait(.5);
    }
}

Step 3 Include bootloader.cpp in your first firmware

Before you can update firmware using serial you first must update the firmware using SWD along with the bootloader included in your binary.

#include "mbed.h"
extern void bootloader(void);
//...
main(){
//...
bootloader();
}

Step 4 Include reference to bootloader in serial updates

Once the bootloader is on the uControler you should not include the bootloader in binaries that you want to update over serial. Instead you can access the bootloader by using the following:

#include "mbed.h"

void *(*bootloader)(void) = (void *(*)(void))0x7001; //Address of bootloader + 1 (For some reason)
//...
main(){
//...
bootloader();
}

IF YOU ARE PROGRAMMING USING A PROGRAMMER (SWD OR JTAG) AND NOT SERIAL MAKE SURE TO INCLUDE THE BOOTLOADER OR OTHERWISE IT WILL MOST LIKELY BE ERASED OR OVERWRITTEN